saga/seata-saga-statelang/src/main/java/io/seata/saga/statelang/parser/utils/IOUtils.java
<reponame>tyc1210/seata-1/*
 *  Copyright 1999-2019 Seata.io Group.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package io.seata.saga.statelang.parser.utils;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;

/**
 * IOUtils
 * copy from commons-io
 *
 * @author lorne.cl
 */
public class IOUtils {

    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    public static String toString(InputStream input, String encoding) throws IOException {
        StringWriter sw = new StringWriter();
        copy(input, sw, encoding);
        return sw.toString();
    }

    public static void copy(InputStream input, Writer output, String encoding) throws IOException {
        if (encoding == null) {
            copy(input, output);
        } else {
            InputStreamReader in = new InputStreamReader(input, encoding);
            copy(in, output);
        }
    }

    public static void copy(InputStream input, Writer output) throws IOException {
        InputStreamReader in = new InputStreamReader(input);
        copy(in, output);
    }

    public static int copy(Reader input, Writer output) throws IOException {
        char[] buffer = new char[DEFAULT_BUFFER_SIZE];
        int count = 0;
        int n = 0;
        while (-1 != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }
}